Inverse multiplexing for ATM (IMA) is a protocol at the cell level which groups a number of physical links into one higher speed virtual link. IMA interfaces are provided at each end of a link group. In a transmit direction, the cell stream received from the ATM layer is distributed on a cell by cell basis across the multiple links within the link group. At the far end, the receiving IMA recombines the cells from each link on a cell by cell basis, reforming the original cell stream. The re-combined stream is then passed up to the ATM layer and processed in the conventional manner.
However, IMA virtual link bandwidth may fluctuate resulting in a congested state where quality of service (QoS) guarantees (e.g. cell loss ratio) can no longer be met. Hence, a dynamic bandwidth management mechanism would be desirable to ensure that quality of service guarantees are met at all times. With such a mechanism it would be possible to preserve ATM QoS guarantees, provided flexible bandwidth loss distribution, provide a predictable effect on ATM connections and make efficient use of the available bandwidth.